The presently disclosed embodiments relate generally to imaging members for use in electrostatographic, including digital, apparatuses. More particularly, the embodiments pertain to processes for preparing the substrate of such imaging members which use lasers. The processes provide a precise and cost-effective manner in which to form the substrate.
Electrophotographic imaging members, e.g., photoreceptors, typically include a photoconductive layer formed on an electrically conductive substrate. The photoconductive layer is an insulator in the substantial absence of light so that electric charges are retained on its surface. Upon exposure to light, charge is generated by the photoactive pigment, and under applied field charge moves through the photoreceptor and the charge is dissipated.
In electrophotography, also known as xerography, electrophotographic imaging or electrostatographic imaging, the surface of an electrophotographic plate, drum, belt or the like (imaging member or photoreceptor) containing a photoconductive insulating layer on a conductive layer is first uniformly electrostatically charged. The imaging member is then exposed to a pattern of activating electromagnetic radiation, such as light. Charge generated by the photoactive pigment move under the force of the applied field. The movement of the charge through the photoreceptor selectively dissipates the charge on the illuminated areas of the photoconductive insulating layer while leaving behind an electrostatic latent image. This electrostatic latent image may then be developed to form a visible image by depositing oppositely charged particles on the surface of the photoconductive insulating layer. The resulting visible image may then be transferred from the imaging member directly or indirectly (such as by a transfer or other member) to a print substrate, such as transparency or paper. The imaging process may be repeated many times with reusable imaging members.
An electrophotographic imaging member may be provided in a number of forms. For example, the imaging member may be a homogeneous layer of a single material such as vitreous selenium or it may be a composite layer containing a photoconductor and another material. In addition, the imaging member may be layered. These layers can be in any order, and sometimes can be combined in a single or mixed layer.
Typical multilayered photoreceptors or imaging members have at least two layers, and may include a substrate, a conductive layer, an optional charge blocking layer, an optional adhesive layer, a photogenerating layer (sometimes referred to as a “charge generation layer,” “charge generating layer,” or “charge generator layer”), a charge transport layer, an optional overcoating layer and, in some belt embodiments, an anticurl backing layer. In the multilayer configuration, the active layers of the photoreceptor are the charge generation layer (CGL) and the charge transport layer (CTL).
There are different conventional processes with which to make these photoreceptors, however, the conventional processes often experience disadvantages. For example, the substrate requires many steps in its preparation. All photoreceptors must have an insulating barrier between the CGL and the substrate. To prepare an insulating barrier on the substrate, conventional processes involve preparing the surface of the substrate to a predetermined surface roughness and then cleaning the substrate prior to dip coating to form a chemical layer (e.g., an oxide layer) on the substrate surface. After the dip coating, the substrate must be dried in oven conditions which are often difficult to achieve. In addition, the step of preparing the rough surface of the substrate requires lathing to obtain the desired dimensional properties. As lathing uses components such as diamonds and cooling fluids, and involves extensive cleaning and labor, the process becomes quite costly. Thus, conventional processes used to make such photoreceptor layers, while suitable for their intended purpose, do suffer from disadvantages.
The term “photoreceptor” or “photoconductor” is generally used interchangeably with the terms “imaging member.” The term “electrostatographic” includes “electrophotographic” and “xerographic.” The terms “charge transport molecule” are generally used interchangeably with the terms “hole transport molecule.”